Water is the most important natural resource in the world, because life cannot exist without it. The presence of a safe and reliable source of water is thus an essential prerequisite for the establishment of a stable community (Hassan & Elhassan 2016).
The contamination of water is one of the real concerns of the whole world. Heavy metals, toxic waste and various effluents from anthropogenic sources as well as industrialization cause the contamination of river water. These pollutants have adverse effects on the health of human and other living beings in terrestrial and aquatic environments, as well as they affect the food chain (Singh & Sao 2015). The quality of the Nile water is a matter of serious concern due to the expansion of industrial, agricultural and entertainment activities in addition to the poorly constructed drainage and sewerage system (Goher et al. 2015; Hassouna et al. 2014a).
Regular monitoring of drinking water at the source of supply and at the consumer end is of primary importance for the creation of a database combining general and chemical characteristics of water, which can help to significantly reduce health hazards (Cieszynska et al. 2012; Faridi et al. 2012). The Water Quality Index is a mathematical tool for summarizing the water quality data in simple terms. It reflects the level of water quality in rivers, streams and lakes (Abdel-Satar et al. 2017; Kükrer & Mutlu 2019). Heavy metals play a major role in water pollution since they are toxic to aquatic animals and may become a threat to humans. The main source of heavy metals in the Nile River is the drainage of domestic sewage, industrial waste and surface runoff of pesticides and herbicides from agricultural land (Ibrahim 2007). Heavy metals (HMs) contamination and accumulation is a critical problem around the world due to their toxicity, abundant sources, non-biodegradable properties and accumulation (Bifeng et al. 2017; Ali 2019).
In ancient times, Bahr Yusuf was a natural branch of the Nile, connected with the Fayoum depression during the Paleolithic period. Without this natural connection, Fayoum would still be a dry desert depression, similar to other depressions existing in the western desert of Egypt (Omar 2013). The natural canal was passing through the natural relief of the mountain bordering the Libyan desert, with a length of 16 km and a width of 1.5 km, and connected the Nile with Moeris Lake (now known as Qarun Lake), which was used as a reservoir for the Nile water during flood periods. During the 12th dynasty, King Amenemhat III constructed an artificial canal (Old Bahr Yusuf Canal) to restore about 13 BCM of flood water in Moeris Lake every year. The artificial canal, 15 km long, 5 m deep and trapezoidal in shape with a width of 600 m at the bottom, was dug along the natural incline of the valley (Chanson 2004). About 230 BC, the old Bahr Yusuf eventually became neglected. Qarun Lake (Moeris Lake) has been converted to a saline lake, which currently receives only drainage water from the Fayoum province via several drains, mainly El-Bats and El-Wadi (Goher et al. 2018).
At present, Bahr Yusuf is an artificial channel that supplies the Nile water to the Fayoum province via the Ibrahimia Canal. The Ibrahimia Canal, which was dug in 1873 in the city of Assiut, 544.8 km downstream from the Aswan High Dam, flows north for about 61 km to the city of Dairut, where it divides into five canals (Sahelyia, Diroutia, Badraman, Abo Gabal, and Irad Delgaw Canals), in addition to two main branches. One branch (the eastern one) is theIbrahimia Canal proper (Ibrahimia canal downstream), while the other one (the western branch) is the Bahr Yusuf Canal (Chanson 2004; El Quosy & Khalifa 2017).
Despite the great importance of the Bahr Yusuf Canal, which is the main source of freshwater for the Fayoum province, supplying two thirds of the Nile water quota, it has not attracted sufficient interest from scientists and has not been sufficiently researched as an aquatic ecosystem. Very limited research concerned mostly the quality of water in the canal (Mahmoud 2016; Bream 2017) and most research focused on Bahr Yusuf as part of the irrigation system in the Fayoum governorate.
The present work is the first study to assess the suitability of water from the Bahr Yusuf Canal for different purposes. Therefore, this study was carried out to achieve the following objectives: (a) to assess spatial-temporal variations of physicochemical characteristics and trace element levels in the water of the canal; (b) to indicate the suitability of water for various uses such as drinking, irrigation and aquatic life habitat using different indices of water quality and heavy metal pollution load; (c) to assess the possible chemical toxicity and health hazards due to the presence of trace elements in the canal water using the USEPA Model.
As mentioned above, Bahr Yusuf connects the Nile River via the Ibrahimia Canal. With a length of about 315 km, the Bahr Yusuf Canal runs north to irrigate the land of western Assiut, western El-Menyia, Beni-suef, Fayoum, and Giza governorates. The Bahr Yusuf Canal takes a zigzag course for about 276 km until it reaches the Fayoum depression through the Hawara Gap where the Lahoon regulator is located.
At Al-Lahoon barrages, the Bahr Yusuf Canal proper branches into many streams, including three main canals, the first one is the Giza Canal (or “Beni-Suef” – Bahr Yusuf segment) that diverts northeast in the northwestern Beni-Suef and Giza districts. Whereas the other two branches, known as Bahr Yusuf and Bahr Hassan Wasef canals, turn west into the Fayoum depression (MWRI 1992; Hewison 2008; Omar 2014).
In the Fayoum province, the section of the Bahr Yusuf Canal extends over a length of about 24 km, 3–5 m depth and 30–50 m width. Numerous canals receive their water from Bahr Yusuf (the main one being the Bahr Wahby Canal that transports water to northern areas) and distribute it over the Fayoum land. The main distribution point is located at the western end of the city of Fayoum, where the Bahr Yusuf Canal splits into eight channels (Hewison 2008). Bahr Yusuf supplies about 1.613–1.707 BCM y−1 of the Nile water to the Fayoum province, which corresponds to two thirds of Fayoum’s quota (2.42–2.56 BCM y−1) of the Nile water (MWRI/USAID, 2003; Omar 2014). In addition, Bahr Yusuf together with Bahr Hassan Wasef Canals supply water to more than 3.5 million people for various human activities and served about 454700 Feddans (1 Feddan = 4 200m2) of the agricultural land in the Fayoum province (Omar 2014). However, Bahr Yusuf in the Fayoum district is exposed to many sources of pollution, including agricultural runoff and domestic sewage effluents from nearby houses along the two banks of the canal. The present study relates to a section of the Bahr Yusuf Canal in the Fayoum province.
Twelve samples of subsurface water were collected seasonally in 2017 by a 2 l polyvinyl chloride Van Dorn bottle at eleven sites along the Bahr Yusuf Canal in the Fayoum Province (Fig. 1). The samples were collected on the 20th day of February, May, August and November, from 8 a.m. to 2 p.m. Details of surface water sampling locations along with their longitude and latitude are presented in Table 1. The water level followed the following order during the present study:
autumn<winter<spring<summer
Characteristics, longitude and latitude of the sampling locations
Location | Features of the locations | Latitude (N) | Longitude (E) |
---|---|---|---|
1 | Hawara before Tafreea (Tema Bridge) (El-Lahon) | 30°27’55” | 32°32’50.7” |
2 | Hawarat Adnan | 30°27’56” | 32°32’50.6” |
3 | Ezbet Al-Khawaja (Taha) | 30°27’58” | 32°32’50.5” |
4 | Ezbet Ameen | 30°27’61” | 32°32’51.0” |
5 | Manshiet Kamal | 30°27’64” | 32°32’52.0” |
6 | The upper bridge at Dmishqin | 30°23’66” | 32°33’34.0” |
7 | Kobry El-Fell | 30°02’54” | 32°34’74.7” |
8 | Hawarat Elmaktaa | 29°91’16” | 32°36’17.6” |
9 | Village of Snovr | 29°24’91” | 32°39’45.7” |
10 | Outlet Qhafa (drinking water plant) | 29°16’18” | 32°43’56.3” |
11 | Kobry Baghos | 29°15’65” | 32°43’58.4” |
12 | El-Sofi | 28°94’18” | 32°44’23.6” |
Water temperature, EC and pH values were measured in situ, using hydro lab model Orion Research Ion Analyzer 399A. Transparency was measured using a Secchi disk (diameter 30 cm).
Water samples were kept in a polyvinyl chloride Van Dorn bottle in an ice box and analyzed in the laboratory. Physical and chemical parameters of water samples were determined in compliance with standard methods of the American Public Health Association (APHA 2005). Total solids (TS) were measured by evaporating a known volume of a well-mixed sample at 105°C. TDS were determined by filtrating a known volume of a sample by GF/C filters and evaporating it at 180°C. TSS were directly determined by subtracting TDS from TS (TS – TDS). Dissolved oxygen (DO) was determined by using the modified Winkler method. Biochemical oxygen demand (BOD) was determined by using the 5-day method. Chemical oxygen demand (COD) was determined using the potassium permanganate method. Water alkalinity was determined immediately after sampling, using phenolphthalein and methyl orange as indicators. Chlorides were measured using Mohr’s method and sulphates – by turbidimetric methods. Calcium and magnesium were determined by direct titration using EDTA solution; Na+ and K+ were determined directly using the Jenway Flame Photometer PFP (U.K.). Concentrations of NO2-N, NO3-N, NH4-N,
Boron and heavy metals (Zn, Cd, Cu, Fe, Mn, Ni, Pb, Cr, B, and Al) were measured using an atomic absorption reader (SavantAA AAS with GF 5000 Graphite Furnace) according to Geugten (1981) and APHA (2005), respectively. Chlorophyll-
where E – absorbance at wavelength indicated, L – cuvette light path in centimeter; Ve – volume of extraction solvent in ml; Vf – volume of a sample filtered in l and concentrations in μg l−1.
The one-way ANOVA test was used to determine spatial and temporal significant differences for the obtained data (Leščešen et al. 2015) using Excel-Stat software (2013). In addition, standard deviation and pair coefficients of correlations (r) were calculated.
Four integrated water quality indices were used to examine the suitability of water in the Bahr Yusuf Canal for different uses. Table 2 shows the values and ratings of each index.
Water rating according to different Water Quality Index methods
ATI | OWQI | WAWQI | CWQI) | ||||
---|---|---|---|---|---|---|---|
WQI | Rating | WQI | Rating | WQI | Rating | WQI | Rating |
60–100 | Suitable for all fish species | 90–100 | Excellent | 0–25 | Excellent | 95–100 | Excellent |
51–59 | Suitable only for hardy fish species | 85–89 | Good | 26–50 | Good | 80–94 | Good |
0–50 | Totally unsuitable for normal fish life | 80–84 | Fair | 51–75 | Poor | 65–79 | Fair |
60–79 | Poor | 76–100 | Very poor | 45–64 | Marginal | ||
0–59 | Very Poor | <100 | Unsuitable | 0–44 | Poor |
The index was developed by Wepener et al. (1992) to assess the health of aquatic ecosystems. Since an extensive toxicity database is available for fish, toxic effects of varying water quality on fish have been employed as health indicators of the aquatic ecosystem. In the present study, the following water quality parameters were used: pH, DO, ammonium, TDS, potassium, orthophosphates, Zn, Mn, Cr, Cu, Pb, and Ni. In the case of the ATI, the Solway Modified Unweighted Additive Aggregation function (Wepener et al. 1992; Sarkar & Abbasi 2006) was employed as an aggregation technique:
where qi is the quality of the ith parameter (between 0 and 100), n is the number of determinants in the indexing system and ATI is the final index score value between 0 and 100. Details of qi calculation are presented in Wepener et al. (1992).
The OWQI is a single number that expresses water quality by taking eight water quality parameters (temperature, DO, pH, BOD, TP, TS, fecal coliform, ammonia, and nitrate nitrogen) into account. The OWQI was computed according to Cude (2001):
where n is the number of sub-indices and Si is the sub-index of each parameter. Details of how to calculate the sub-index for each parameter are provided in Cude (2001).
The weighted arithmetic water quality index (WAWQI) classifies the water quality according to the degree of purity by using the most commonly measured water quality parameters. The WQI was calculated using the equation provided by Rown et al. (1972):
Details of the calculation of the quality rating scale (Qi) and the unit weight (Wi) for each parameter are presented in Goher et al. (2014a).
To simplify complex and technical water quality data, the Canadian Council of Ministers of the Environment developed a water quality index (CCME 2001). CWQI was calculated using the following equation:
where 1.732 is the corrected factor; F1 (Scope) represents the percentage of failed variables relative to the total number of variables measured; F2 (Frequency) represents the percentage of individual failed tests relative to the total number of tests; F3 (Amplitude) represents the excursion of failed tests relative to their objectives. Details of the calculation are provided in CCME (2001).
The HPI describes the quality of water with reference to metals and its suitability for drinking (Prasad & Bose 2001). It is based on the weighted arithmetic quality mean method (Mohan et al. 1996):
where Wi is the weight unit of the ith metal (between 0 and 1), n is the number of measured metals and Qi is the sub-index of the ith metal.
K is the proportionality constant
where Ci is the measured value of the ith metal; Si is the standard permissible value of the ith parameter and Ii is the ideal value of the ith metal; in pure water Ii = zero.
Thus equation 8 converts to
Finally, the critical pollution index score for drinking water is 100 (Prasad & Bose 2001).
The human health risk associated with the use of water contaminated with various metals, i.e. the non-carcinogenic risk was assessed using the Hazard Quotient (HQ) and the Hazard Index (HI), which are based on the USEPA module (USEPA 1989):
where HQi is the Hazard Quotient (HQ) for the ith metal.
Where
and
where HQoral is the quotient of hazard via ingestion (unitless); Ci is the concentration of a heavy metal in water (mg l−1); IR is the ingestion rate (l day−1); EF is the exposure frequency (days year−1); ED is the exposure duration (years), BW is the body weight in (kg); AT is the average time (days) and RFD0 is the oral reference dose (mg kg−1 day−1). In the present study, EF = 365 days; ED = 70 years, BW = 70 kg and AT = 25550 days (USEPA 2001).
where
where HQdermal is the quotient of hazard via dermal contact (unitless); Ci is the heavy metal concentration in water (mg cm−3); SA is the skin surface area available for contact (cm2); ED is the exposure duration (years); tevent is the event duration (h event−1); Kp is the dermal permeability coefficient of the target compound in water (cm h−1); EV is the event frequency (event day−1); EF is the exposure frequency (days year−1); BW is the body weight (kg); AT is the average time (days) and RfDo is the oral reference dose (mg kg−1 day−1); RfDABS is the absorbed reference dose (mg kg−1 day−1) and ABSGi is the fraction of a contaminant absorbed in the gastrointestinal tract (dimensionless) in the critical toxicity study. According to USEPA (2004): EF = 350 days, ED = 70 years, SA = 18000 cm2, EV = 1.0 event day−1, tevent = 0.58 h event−1, BW = 70 kg and AT = 10 950 days. The oral reference dose (RfD0), the gastrointestinal absorption factor and the dermal permeability coefficient (Kp) are presented in Table 3.
The reference dose level (RfD0; mg kg−1 day−1), the absorbed factor (ABS) and the dermal permeability coefficient (Kp; cm h−1) for boron and the measured heavy metals
Chemicals | Chemicals | ||||||
---|---|---|---|---|---|---|---|
Al | 1 | 1 | 0.001 | Fe | 0.7 | 1 | 0.001 |
B | 0.2 | 1 | 0.001 | Mn | 0.024 | 0.04 | 0.001 |
Cd | 0.0005 | 0.05 | 0.001 | Ni | 0.02 | 0.04 | 0.0002 |
Cr | 0.003 | 0.013 | 0.001 | Pb | 0.015 | 1 | 0.0001 |
Cu | 0.04 | 1 | 0.001 | Zn | 0.3 | 1 | 0.0006 |
a: USEPA (2018a); b: USEPA (2004)
The seasonal distribution of the physicochemical characteristics of water in the Bahr Yusuf Canal is presented in Table 4, while Table 5 shows the guidelines for drinking water developed by WHO (2017), USEPA (2018a,b) and EWQS (2007), and for irrigation water according to Ayers & Westcot (1985), in addition to aquatic life criteria defined by CCME (2007).
Physical and chemical characteristics of water in the Bahr Yusuf Canal in 2017
Parameter | Winter Range | Spring Range | Summer Range | Autumn Range | Annual Average |
---|---|---|---|---|---|
Temperature (°C) | 19.0–21.0 | 25.6–26.3 | 29.4–30.5 | 24.5–26.0 | 25.2±3.61 |
Transparency (cm) | 34.0–78.0 | 66.0–94.0 | 67.0–94.0 | 53.0–80.0 | 73.92±10.53 |
EC (μS cm−1) | 406–495 | 353–505 | 313–446 | 518–592 | 458.13±69.4 |
TDS (mg l−1) | 243.6–297 | 211.8–303 | 187.8–267.6 | 310.8–355.2 | 274.9±41.65 |
TSS (mg l−1) | 21.8–78.8 | 10.0–35.0 | 7.2–19.40 | 21.2–50.8 | 24.7±13.06 |
TS (mg l−1) | 273.6–375.8 | 227.8–327 | 204.6–287 | 337.6–381.6 | 300±49.75 |
pH | 7.7–7.86 | 8.17-8.38 | 8.01-8.25 | 7.49–7.92 | 7.95±0.24 |
DO (mg l−1) | 8.19–9.3 | 7.89–9.23 | 7.01–8.69 | 6.52–7.67 | 8.58±0.64 |
COD (mg l−1) | 5.2–8.88 | 5.0–7.8 | 6.18–9.6 | 6.82–10.2 | 7.59±1.31 |
BOD (mg l−1) | 2.93–4.27 | 4.2–6.19 | 4.8–6.32 | 3.76–4.89 | 6.32±0.91 |
NO2-N (μg l−1) | 18.8–45.2 | 4.8–40.2 | 14.2–23.0 | 27.2–38.2 | 23.35±11.06 |
NO3-N (μg l−1) | 162–410 | 52.9–172.1 | 148–315 | 449–707 | 285.8±177.2 |
NH4-N (μg l−1) | 231.6–299.2 | 137.6–192.6 | 11.4–142.4 | 239.16–331 | 209.9±72.68 |
TN (μg l−1) | 500–945 | 365–517 | 436–665 | 1060–1393 | 725±305 |
PO4-P (μg l−1) | 13.6–19.2 | 7.22–12.4 | 8.48–18.82 | 18.67–25.33 | 15.49±5.36 |
TP (μg l−1) | 71–115 | 45.6–95.2 | 45.6–97.8 | 74.2–167 | 83.7±22.57 |
Silicate (mg l−1) | 2.2–2.9 | 3.71–5.94 | 5.73–7.86 | 2.84–6.52 | 4.75±1.67 |
TA (mg l−1) | 122.3–145.7 | 143.4–159.52 | 99.7–126.9 | 105.6–138.8 | 130.2±16.08 |
3.6–9.6 | 2.4–4.8 | 2.16–4.92 | 2.4–7.2 | 4.29±1.88 | |
HCO3− (mg l−1) | 132.1–161.7 | 166.5–187.3 | 114.4–148 | 122.8–161.8 | 150.1±19.18 |
Cl (mg l−1) | 18.96–27.62 | 20.39–24.36 | 15.22–22.29 | 28.73–31.94 | 24.24±4.7 |
16.9–19.17 | 11.62–16.74 | 9.88–13.66 | 14.89–17.54 | 15.2±2.56 | |
Na (mg l−1) | 20.16–22.38 | 18.26–19.68 | 17.73–18.96 | 22.18–23.28 | 20.32±1.89 |
K (mg l−1) | 5.8–6.41 | 4.8–5.44 | 4.3–4.89 | 5.4–6.55 | 6.1±0.73 |
TH | 107.7–129.5 | 97.48–126.58 | 84.29–112.55 | 129.42–143.44 | 118.51±14.97 |
Ca (mg l−1) | 18.52–22.7 | 16.47–21.78 | 14.65–20.45 | 23.07–26.03 | 20.96±2.86 |
Mg (mg l−1) | 14.7–17.46 | 13.5–17.34 | 11.4–14.74 | 17.2–18.92 | 15.9±1.92 |
B (μg l−1) | 25.28–47.22 | 26.39–49.44 | 28.61–48.89 | 45.28–77.22 | 44.07±12.91 |
Chlorophyll- |
14.38–22.95 | 21.36–38.2 | 31.69–44.47 | 13.96–33.28 | 26.59±8.62 |
TA: total alkalinity; TH: total hardness
Guidelines for the measured parameters in mg l−1 (except Temp., EC and pH) according to national and international permissible levels
Parameter | Drinking Water | Irrigation | Aquatic life | Parameter | Drinking Water | Irrigation | Aquatic life | ||||
---|---|---|---|---|---|---|---|---|---|---|---|
EWQS | WHO | EPA | EWQS | WHO | EPA | ||||||
Temp. (°C) | < 35 | 8–28 | 250 | 250 | 250 | 960 | |||||
EC(μS cm−1)a,b | 2000 | 3000 | Naa,b | 200 | 919 | ||||||
pHa,b,c | 6.5–8.5 | 8.5 | 6.5–8.5 | 8.5 | 6.5–9 | Kb | 2 | ||||
TDSa,b,c | 1000 | 500 | 500 | 2000 | 500 | THa | 500 | 500 | |||
DOac | 6 | > 4 | > 5.5 | Caa,b | 75 | 75 | 60 | ||||
BODa | 3 | 3* | Mga,b | 50 | 50 | 400 | |||||
CODa | 10 | 10 | Ala,b,c | 0.2 | 0.2 | 0.2 | 5 | 0.1 | |||
NO2-Na,c | 0.06 | 0.9 | 1 | 0.06 | Babc | 0.5 | 2.4 | 0.5–2 | 1.5 | ||
NO3-Na,b,c | 10 | 11 | 10 | 10 | 2.93 | Cda,b,c | 0.003 | 0.003 | 0.005 | 0.01 | 0.001 |
NH4-Na,b,c | 0.41 | 0.2 | 5 | 1.27–0.077** | Cra,b,c | 0.05 | 0.05 | 0.1 | 0.1 | 0.01 | |
PO4-Pb | 2 | Cua,b,c | 2 | 2 | 1.3 | 0.2 | 0.004 | ||||
TPa | 1 | Fea,b,c | 0.3 | 0.3 | 5 | 0.3 | |||||
TA | 250 | > 20 | Mna,b,c | 0.4 | 0.1 | 0.05 | 0.2 | 0.05 | |||
3 | Nia,b,c | 0.02 | 0.07 | 0.1 | 0.2 | 0.025 | |||||
610 | Pba,b,c | 0.01 | 0.01 | 0.015 | 0.2 | 0.007 | |||||
Cla,b,c | 250 | 200 | 250 | 1036 | 120 | Zna,b,c | 3 | 4 | 5 | 5 | 0.05 |
Reference | EWQS | WHO | EPA | Ayers & Westcot | CCME | EWQS | WHO | EPA | Ayers & Westcot | CCME | |
2007 | 2017 | 2018a,b | 1985 | 2007 | 2007 | 2017 | 2018a,b | 1985 | 2007 |
abc The parameter used to calculate CWQI and WAWQI for (a) drinking, (b) irrigation and (c) aquatic life purposes. TA: Total alkalinity; TH: Hardness, * BOD according to EU (1975) **Ammonia permissible level dependent on Temperature (20–30°C) and pH value (7.5–8.5)
The results showed that the water temperature was within ordinary values suitable for fish and aquatic organisms (8–28) throughout the year with a slight elevation in summer with a large significant temporal difference (
The decrease in the flow level in the Bahr Yusuf Canal in autumn leads to the concentration of ions, which results in an increase in the EC levels, where EC and the water level are inversely related (Islam et al. 2015). EC varied in the ranges of 406–495, 353–505, 313–446 and 518–592 μs cm−1 in winter, spring, summer, and autumn, respectively, with a large significant temporal difference (
TS, TDS, and TSS were varied in the ranges of 204.6–375.8, 187.8–355.2 and 7.20–78.80 mg l−1, respectively. TSS showed an opposite trend compared to transparency values, with the highest values recorded in autumn, while the lowest TSS content was recorded in summer.
The pH values were within the acceptable ranges for different applications (Tables 4 and 5). They were in the alkaline range (7.49–8.38), reflecting an increase in the photosynthetic activity of planktonic algae, with a large significant temporal difference (
DO, BOD and COD were varied in the ranges of 6.52–9.30, 2.93–6.32 and 5.0– 10.2 mg l−1, respectively, with significant seasonal variations (
Nutrient salts play an important role in the productivity of aquatic ecosystems by supporting the food chain of phytoplankton and zooplankton as well as fish. The basic nutrient salts show large significant temporal differences (
In the case of inorganic nitrogen forms, nitrate dominated, followed by ammonia and nitrite. The increase in NO2− and NO3− concentrations in winter may be due to the decomposition of organic matter present in wastewater, where
Orthophosphate and total phosphorus showed a significant increase during the drought period. The results were consistent with those obtained by Goher et al. (2014a) and El Degway (2016). Nitrogen and phosphorus are important components of a healthy aquatic ecosystem, but elevated levels may have a negative impact on water bodies, as an increase in algal blooms due to nutrient abundance can cause “hypertrophication” of aquatic systems (Anonymous 2015). The determined content of nitrogen and phosphorus indicates that the water in the Bahr Yusuf Canal is between mesotrophic and eutrophic (Dodds & Smith 2016).
The fluctuation in the concentration of silicates did not follow the distribution pattern of other nutrients, with a high content during the hot season (high water level). These results indicate that the discharged wastewater did not play a major role in the distribution of silica in the Nile water (Abdel-Satar et al. 2017). The main factors affecting the reactive silicate distribution are the uptake by diatoms, silicate rock weathering, as well as water movement, turbulence, temperature, pH and salinity, especially during floods (Ahlers et al. 1991).
Chlorophyll-
On the basis of chlorophyll-
The main components of alkalinity of surface water are carbonates and bicarbonates (Muhammad et al. 2000).
Calcium and magnesium values were in the range of 14.65–26.03 and 11.4–18.9 mg l−1, respectively, with large seasonal variations (
The mean levels of Ba, Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn in the water of the Bahr Yusuf Canal were as follows: 44.07 ± 12.91, 72.22 ± 23.7, 4.872 ± 1.351, 14.06 ± 3.3, 8.67 ± 2.56, 268.13 ± 71.59, 37.53 ± 9.97, 32.63 ± 7.19, 31.85 ± 6.55 and 27.99 ± 4.91 μg l−1, respectively (Fig. 2). The concentrations of boron and most heavy metals showed highly significant differences (
Boron is a mobile trace element, an essential micronutrient for plants, animals and aquatic life, but it becomes toxic in higher concentrations (Zhang et al. 2018; CCME 2009). Rock weathering is the main source of B, but anthropogenic activities also contribute, though to a lesser extent, as a source of B in water bodies (Emirooğlu et al. 2010; Gaillardet et al. 2003). Its compounds are used in the manufacture of glass, soap and detergents and as flame retardants. The borate content in surface water may increase as a result of wastewater discharges (WHO 2017). Boron is present in freshwater as nonionized boric acid and negatively charged borate ion
Both Fe and Mn are commonly found in water and are essential elements required in small amounts by all living organisms. The presence of iron or manganese in drinking water can affect the smell, taste or color of the water (NSF 2018). Fe and Mn levels fluctuated in the range of 169.55–568.4 and 34.27–69.35 μg l−1 with high significant temporal variations (
The level of aluminum was generally within the allowable national and international standard levels for drinking and irrigation water (200 and 5000 μg l−1, respectively). Whereas it was higher than the permissible national level for aquatic life (100 μg l−1) in autumn and winter, which may be related to the effect of wastes discharged into the canal during the drought period. It ranged from 49.27 to 145.77 μg l−1 with highly significant differences between the sites (
Nickel at many sites exceeded the acceptable limits for drinking water (20 μg l−1) and aquatic life (25 μg l−1); it was in the range of 16.07–47.56 μg l−1, with a highly significant temporal difference (
The concentrations of Cu, Zn and Cr were below the guidelines for drinking and irrigation water, while Cu and Cr exceeded the allowable limits for the aquatic life (Tables 4 and 5). Cu, Zn, and Cr were in the ranges of 3.04–13.94, 16.03–42.18 and 8.62–21.44 μg l−1, respectively, with highly significant temporal variations (
The above results show that most of the water parameters in the Bahr Yusuf Canal increase in the cold (drought) period, particularly in autumn at the lowest water level. On the other hand, the results obtained for the Bahr Yusuf Canal are consistent with the previous studies on the Nile River and its branches. Table 6 shows the obtained results in relation to the Nile River and Nile canals in Egypt.
Water parameters of the Bahr Yusuf Canal compared to the Nile River and other Egyptian Nile canals
Parameters | Units | Water resource | ||||||
---|---|---|---|---|---|---|---|---|
Nile River | Nile River | Bahr Yusuf Canal | El-Sharkawia Canal | Ismailia Canal | Beni-Suef Water Resources | Bahr Yusuf Canal | ||
Temp. | °C | 17.8–30.7 | 24.5–25.16 | 14.50–33.10 | 16–33 | 19–30.5 | ||
Transparency | cm | 15–950 | 50–150 | 35–120 | 34–94 | |||
EC | ms cm−1 | 210–1014 | 424.6–797.7 | 313–531 | 350–544 | 319–1473 | 313–592 | |
TDS | 128.8–409.9 | 137–659 | 260.6–518.6 | 212.5–348.2 | 210–365 | 204–943 | 187.8–355.2 | |
TSS | mg l−1 | 10.67–46.00 | 39–176 | 7.2–78.8 | ||||
TS | 230.5–358.8 | 286–528 | 204.6–381.6 | |||||
pH | 7.43–8.68 | 7.3–9.0 | 7.89–8.59 | 7.09–8.46 | 7–7.93 | 7.49–8.38 | ||
DO | 3–13.2 | 1.60–9.68 | 5.78–9.98 | 7.01–9.3 | ||||
BOD | 1.2–8.0 | 1.40–6.84 | 0.3–7.18 | 2.93–6.32 | ||||
COD | 3.78–14.04 | 3.68–15.08 | 5–10.2 | |||||
CO3 | 5.20–20.09 | 0.0–22.2 | 2.16–9.6 | |||||
HCO3 | 122–517.4 | 94.1–324.6 | 110.4–186.1 | 105.9–162.4 | 128–297 | 114.35–187.2 | ||
Cl | 6.18–96.80 | 23.46-84.47 | 15.10–23.11 | 14.25–33.16 | 21–274 | 15.22–31.94 | ||
SO4 | mg l−1 | 5–50 | 3.83–58.94 | 31.7 -86.19 | 14.60–34.46 | 8.71–98.8 | 20–118 | 9.88–19.17 |
Ca | 18.4–59.6 | 9.43–41.16 | 29.58 to 53.75 | 16.33–30.54 | 24.17–38.82 | 34–79 | 14.65–26.03 | |
Mg | 18.5–52.6 | 6.08–44.93 | 10.04–15.09 | 11.05–22.40 | 9.78–17.62 | 9–24 | 11.4–18.9 | |
TH | 102–169.34 | 84.29–143.44 | ||||||
Na | 14.4–99.5 | 11.25–72.7 | 20.86–57.58 | 19.73–41.18 | 15.14–39.7 | 18–204 | 17.73–23.28 | |
K | 1.4–6.9 | 3.67–12.08 | 1.51–5.09 | 8.06–12.35 | 5.77–8.89 | 2.5–16 | 4.3–6.4 | |
NO3-N | 0–23.8 | 3–1878 | 1320–4930 | 24.37–177.3 | 31–584 | 300–16000 | 52.92–707 | |
NO2-N | μg l−1 | 0.5–6943 | UDL–460 | 3.55–19.64 | 2–27 | 4.8–45.2 | ||
NH4-N | 21–17928 | 119.0–1793.6 | 88–569 | 111.4–331 | ||||
TN | mg l−1 | 0.52–139 | ||||||
PO4-P | 4–383 | 5.69–52.43 | 8–399 | 7.22–25.33 | ||||
TP | 15–998 | 35.43–251.8 | 38–480 | 44.1–167 | ||||
SiO3 | 0.39–14.62 | 1.50–10.95 | 0.37–8.78 | 2.2–7.86 | ||||
Ba | UDL | 20–225 | 25.83–77.22 | |||||
Fe | 199–2211 | 490–2900 | 125.8–1478.5 | 109–223.9 | 13–1415 | 169.55–460.5 | ||
Mn | 30–298 | 104–850 | 1.80–119.00 | 20–483 | 37–713 | 23.29–69.35 | ||
Zn | μg l−1 | 50–700 | 10–115 | UDL | 1.60–40.40 | 2–127 | <1–1700 | 16.03–42.18 |
Cu | UDL–170 | 10–51 | UDL | 0.60– 4.12 | 3–21 | <1–1080 | 3.04–13.94 | |
Ni | 1–33 | UDL | 1.75–20.20 | 0.0–25 | 16.07–47.56 | |||
Cr | 1.7–467 | 5.20–25.20 | 8.62–21.44 | |||||
Cd | UDL–5 | 0.2–8.1 | UDL | 0.00–1.21 | 0–3 | <1–400 | 1.86–8.25 | |
Pb | 163–402 | 5–51 | UDL | 3.40–32.60 | 11–34 | 17.62–49.62 | ||
Al | 370–2800 | 55–45400 | 1608–2545 | 49.27–145.77 | ||||
Reference | Elnazer et al. (2018) | Abdel-Satar et al. (2017) | Mahmoud et al. (2016) | El-Degwy (2016) | Goher et al. (2014a) | Melegy et al. (2014) | Present study |
UDL = under detection limit
Several indices were used to assess the water quality in the Bahr Yusuf Canal, including the Aquatic Toxicity Index (ATI), the Canadian Water Quality Index (CWQI), the Oregon Water Quality Index (OWQI) and the Weighted Arithmetic Water Quality Index (WAWQI). In the present study, seven water parameters were selected to compute the OWQI (temperature, DO, pH, BOD, TP, TS, ammonia and nitrate nitrogen), which is used to assess the quality of water with respect to general recreational use, including fishing and swimming (Sarkar & Abbasi 2006). To calculate the Aquatic Toxicity Index (ATI), 12 water parameters (DO, TDS, pH,
Table 7 shows the values of WQIs and the water grades of the Bahr Yusuf Canal for different modules. The OWQI score ranged from 58.82 to 64.77, with a mean value of 61.6 for the whole canal. These results indicate the unsuitability of the canal’s water for recreational use, with water quality classified between poor and very poor for all sampling sites. On the other hand, the ATI results give an indication about the suitability of water quality for all fish species, where ATI ranged from 87.77 to 90.26. According to Poonam (2013), the water quality varies according to the type of use. Based on the CWQI results, the canal water was classified as fair (WQI =73), good (WQI =92) and marginal (WQI=64) for drinking, irrigation and aquatic life, respectively. The CWQI indicated that the water in the Bahr Yusuf Canal may be suitable to some extent for drinking and irrigation, but it is an unsuitable habitat for aquatic life. The WAWQI classified the water quality according to the degree of purity using the most commonly measured water quality parameters (Tyagi et al. 2013). It also describes the suitability of surface water sources for human consumption (Chandra et al. 2017). According to WAWQI, the water in the Bahr Yusuf Canal is classified as excellent, from good to poor, and from good to excellent for irrigation, drinking and aquatic life, respectively. The corresponding values of WAWQI were in the range of 0.87–2.02, 36.09–65.36 and 17.16–39.03, respectively.
WQI and their categorization of Bahr Yusuf water in 2017 for different purposes
Location | OWQI | ATI | CWQI | WAWQI | ||||
---|---|---|---|---|---|---|---|---|
Drinking | Irrigation | Aquatic life | Drinking | Irrigation | Aquatic life | |||
1 | 62.46 |
90.26 |
78 |
92 |
73 |
30.09 |
0.87 |
17.16 |
2 | 63.82 |
89.49 |
74 |
92 |
65 |
50.34 |
1.46 |
28.51 |
3 | 58.82 |
88.86 |
73 |
91 |
65 |
52.35 |
1.93 |
37.77 |
4 | 59.38 |
89.23 |
76 |
92 |
69 |
54.94 |
1.99 |
38.59 |
5 | 62.72 |
88.7 |
72 |
92 |
63 |
51.75 |
2.00 |
38.84 |
6 | 64.77 |
88.34 |
75 |
91 |
67 |
44.67 |
1.89 |
37.04 |
7 | 62.15 |
88.63 |
73 |
91 |
63 |
51.90 |
1.81 |
35.44 |
8 | 60.9 |
89.14 |
73 |
92 |
65 |
59.11 |
1.74 |
34.28 |
9 | 60.27 |
88.45 |
72 |
92 |
65 |
65.36 |
1.83 |
35.85 |
10 | 61.11 |
87.77 |
71 |
93 |
65 |
57.02 |
2.02 |
39.03 |
11 | 60.85 |
87.93 |
73 |
92 |
66 |
53.72 |
1.66 |
32.67 |
12 | 59.53 |
87.8 |
71 |
91 |
60 |
45.34 |
1.86 |
35.90 |
Overall | 61.6 |
88.34 |
73 |
92 |
64 |
52.31 |
1.76 |
34.26 |
It is worth mentioning that different water quality results and water quality categories are related to the type of consumption and the use as drinking water, industrial water and ecosystem preservation (Poonam 2013), as well as to the number and type of water parameters used and the arithmetic and statistical approach of the index used.
Nine heavy metals (Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) were selected to assess the contamination of water in the Bahr Yusuf Canal with metals, based on the Heavy Pollution Index (HPI). The HPI is a comprehensive tool or a rating model that assesses the overall water quality according to the composite effects of individual heavy metals (Herojeet et al. 2015; Vetrimurugan et al. 2017). Table 8 shows that the Heavy Pollution Index for water in the Bahr Yusuf Canal ranged from 104.44 to 206.32, from 16.81 to 38.48 and from 219.07 to 472.24 for drinking water, irrigation water and aquatic life, respectively. These results demonstrate that all the studied metals did not have a polluting effect for irrigation use, but the Bahr Yusuf Canal suffers from different levels of contamination with the studied metals, posing a threat to aquatic life and drinking use. Spatial distributions of the HPI indicate an increase in the potential contamination
Heavy Pollution Index of the measured metals in water of the Bahr Yusuf Canal in 2017 according to guideline levels for drinking, irrigation, and aquatic life
Station | Drinking | Irrigation | Aquatic | |||
---|---|---|---|---|---|---|
HPI | Category | HPI | Category | HPI | Category | |
1 | 104.44 | Polluted | 16.81 | Unpolluted | 219.07 | Polluted |
2 | 153.66 | Polluted | 27.88 | Unpolluted | 347.70 | Polluted |
3 | 198.93 | Polluted | 36.66 | Unpolluted | 461.37 | Polluted |
4 | 206.32 | Polluted | 37.96 | Unpolluted | 472.24 | Polluted |
5 | 200.49 | Polluted | 38.25 | Unpolluted | 468.55 | Polluted |
6 | 193.40 | Polluted | 36.01 | Unpolluted | 444.86 | Polluted |
7 | 187.96 | Polluted | 34.42 | Unpolluted | 427.57 | Polluted |
8 | 187.49 | Polluted | 33.08 | Unpolluted | 415.61 | Polluted |
9 | 187.89 | Polluted | 34.81 | Unpolluted | 430.82 | Polluted |
10 | 201.31 | Polluted | 38.48 | Unpolluted | 469.04 | Polluted |
11 | 175.02 | Polluted | 31.52 | Unpolluted | 393.04 | Polluted |
12 | 191.44 | Polluted | 35.04 | Unpolluted | 434.95 | Polluted |
Overall | 182.36 | Polluted | 33.62 | Unpolluted | 417.46 | Polluted |
downstream, with the lowest values of HPI for different uses of water recorded at site 1 (the mouth or the beginning of the canal). According to the critical HPI value of 100, the data indicate that aquatic organisms living in the Bahr Yusuf Canal may be exposed to greater risks (Table 8). Nadmitov et al. (2015) reported that at HPI > 100, the overall pollution level must be assessed as undesirable for an aquatic ecosystem.
Based on the content of trace elements in the water of the Bahr Yusuf Canal, the non-carcinogenic risk was calculated using the Hazard Quotient (HQ) and the Hazard Index (HI) at 12 locations along the canal. The obtained results showed that HQoral was much higher than HQdermal, ranging from 2.98 × 10−3 to 3.22 × 10−1 and 3.3 × 10−2 to 9.16 × 10−6, respectively, where Cd and Zn recorded the highest and lowest HQoral and HQdermal values, respectively. In general, HQ and HI values ≤ 1 are expected to be safe and HI values ≥ 1 indicate the non-carcinogenic risk. The graphical presentation of HQ and HI values indicates that the entire study area is not exposed to a carcinogenic risk through the consumption and other uses of water from the Bahr Yusuf Canal (Fig. 3). It is worth mentioning that HQ and HI are not a measure of risk but indicate the level of concern (Goher et al. 2015). In fact, the USEPA model of HQ and HI shows a limitation in the Health Risk Assessment. The HQ represents the single effect of one element and the HI represents the sum of these effects. They do not represent the combined or integrated effects of different pollutants (Ma et al. 2014). According to Graf et al. (2007), the combined effect causes the toxicity of pollutants to be additive (synergic) or antagonistic.
The Bahr Yusuf canal is the main source of freshwater for the Fayoum governorate. It is exposed to the deterioration in water quality due to different types of waste that are discharged into this water body, including mainly agricultural runoff and municipal wastes.
The present study was carried out to assess the quality of water in the canal and its suitability for different uses. The study also focused on the determination of the magnitude of pollution, as well as the potential health risk associated with the metal content. Four water quality indices were used to determine the suitability of the canal water for fishing, drinking, irrigation, as well as aquatic life habitat. The water quality varied according to the type of use, the number and type of water parameters used, and the arithmetic and statistical approach of the index applied.
The OWQI indicated the unsuitability of the canal water for recreational use, as the water quality was determined as poor and very poor. Whereas the ATI rated the quality of water in Bahr Yusuf as excellent and suitable for all fish species. CWQI and WAWQI showed that the quality of water in Bahr Yusuf was good, fair & marginal and excellent, from good to poor & from good to excellent for irrigation, drinking and aquatic life, respectively. On the other hand, the HPI results demonstrated that all the studied metals did not have a polluting effect for irrigation use, but the Bahr Yusuf Canal suffers from different levels of contamination with the studied metals, which poses a threat to aquatic life and human health when water is used for drinking. The USEPA module for the human health risk assessment indicates that the entire study area is not exposed to the carcinogenic risk as a result of consumption and other uses of water from the canal.
Last but not least, since the results of the present study showed that the water in the Bahr Yusuf Canal suffers from different levels of pollution, we urge the responsible authorities to prevent the discharge of different types of waste without ensuring an effective pretreatment, to achieve the internationally recommended safe parameters before the waste is discharged into the canal, and to avert further deterioration of the quality of water and, consequently, to carry out its rehabilitation.